From b3f194e54bdbaa4d508488cab24d23c376e235a2 Mon Sep 17 00:00:00 2001 From: Bruno Randolf Date: Wed, 14 Jul 2010 10:53:29 +0900 Subject: [PATCH] ath5k: clean up rxlink handling There were a few places where the sc->rxlink pointer was set to NULL "just in case". This helps nothing - quite to the contrary it is problematic since it can create self-linked rx descriptors in the middle of the list of receive buffers. Here is an example how this could happen (thanks Bob!): cpu 0: cpu 1: ath5k_rx_stop ath5k_tasklet_rx sc->rxlink = NULL; /* just in case */ // following doesn't link used // buffer to prev. ath5k_rxbuf_setup() In the case of ath5k_rx_stop() and ath5k_stop_locked() buffers/descriptors are not changed so rxlink should not be changed as well. In ath5k_intr() we seem to try to work around a hardware bug, as the comment (which is copied 1:1 from the HAL) suggests. I don't see how this could help. Also the HAL does not set rxlink in this case (So where does this code come from? It has been there since the first import of ath5k). Changed to just increment a statistics counter. After this patch rxlink is only set to NULL before we initialize rx descriptors and updated when the descriptors are linked together. Signed-off-by: Bruno Randolf Signed-off-by: John W. Linville --- drivers/net/wireless/ath/ath5k/base.c | 7 ++----- drivers/net/wireless/ath/ath5k/base.h | 1 + 2 files changed, 3 insertions(+), 5 deletions(-) diff --git a/drivers/net/wireless/ath/ath5k/base.c b/drivers/net/wireless/ath/ath5k/base.c index b0e1ca99fcad..0d5de2574dd1 100644 --- a/drivers/net/wireless/ath/ath5k/base.c +++ b/drivers/net/wireless/ath/ath5k/base.c @@ -1728,8 +1728,6 @@ ath5k_rx_stop(struct ath5k_softc *sc) ath5k_hw_stop_rx_dma(ah); /* disable DMA engine */ ath5k_debug_printrxbuffs(sc, ah); - - sc->rxlink = NULL; /* just in case */ } static unsigned int @@ -2633,8 +2631,7 @@ ath5k_stop_locked(struct ath5k_softc *sc) if (!test_bit(ATH_STAT_INVALID, sc->status)) { ath5k_rx_stop(sc); ath5k_hw_phy_disable(ah); - } else - sc->rxlink = NULL; + } return 0; } @@ -2771,7 +2768,7 @@ ath5k_intr(int irq, void *dev_id) * RXE bit is written, but it doesn't work at * least on older hardware revs. */ - sc->rxlink = NULL; + sc->stats.rxeol_intr++; } if (status & AR5K_INT_TXURN) { /* bump tx trigger level */ diff --git a/drivers/net/wireless/ath/ath5k/base.h b/drivers/net/wireless/ath/ath5k/base.h index 86c90f471b74..dc1241f9c4e8 100644 --- a/drivers/net/wireless/ath/ath5k/base.h +++ b/drivers/net/wireless/ath/ath5k/base.h @@ -137,6 +137,7 @@ struct ath5k_statistics { unsigned int mib_intr; unsigned int rxorn_intr; + unsigned int rxeol_intr; }; #if CHAN_DEBUG -- 2.30.2